Dynamo-electric machine.



W. H. POWELL. DYNAMO ELECTRIC MACHINE. APPLICATION FILED FEB. 21. 1915;

1,214,067, v Patented Jan. 30, 1 917.

UNITED STATES PATENT onmon.

WILLIAM H. POWELL, F MILWAUKEE, WISCONSIN, ASSIGNOR TO ALLIS-CHALMERSMANUFACTURING COMPANY, OF MILWAUKEE, WISCONSIN, ACOR'PORATION OFDELAWARE.

Application filed February 27, 1915.

To all whom it may concern:

Be it known that I, \VILLIAM H. POWELL, a citizen of the United States,residing at Milwaukee, in the county of Milwaukee and State ofWisconsin, have invented a certain new and useful Improvement in Dynamo-Electric Machines, of which the following is a specification.

This invention relates in general to dynamo-electric machines, and hasparticular relation to devices for supporting brushes of dynamo-electricmachines in operative position relatively to commutators and to suitableterminals or cross-connectors.

In dynamo-electric machines of comparatively great current capacity,commutators are often required tobe of such great axial length that theordinary type of brush-rod support, offering two bearing points for abrush-rod, does not provide sufficient support for the rod and brushes.Where additional supporting arms for the brush-rod are provided inconnection with the ordinary type of support, the current between thecommutator and that portion of the support that is electricallyconnected to a terminal or a cross-connector is apt to divide unevenly,due to the fact that the path through one of the supporting arms is ofless resistance than that through another. WVith this latter conditionpresent, the supporting arm in the path of least resistance tends tograb or hog the greater portion of the load, on account of the continueddecrease in resistance of this path due to heating of the brushes inthis path.

In accordance with this invention, a brush support of conductingmaterial and providing more than two points of support for a brush-rodis provided, the support being of such construction as to insure aproper division of the current through the supporting arms between thebrushes and the cross-connector or terminal.

It is an object of this invention to provide a brush-rod supportingdevice of improved construction and affording more than two points ofsupport for the rod.

It is a further objectof this invention to provide a brush-rod supportof improved construction and presenting a plurality of separateelectrical paths between the rod and a terminal portion of the support.

These and other objects are attained by this invention, the'variousnovel features of Specification of Letters Patent.

Patented Jan. 30, 1917.

Serial No. 11,405.

which will appear from the description and drawings, disclosing oneembodiment of such invention, and will be particularly pointed out inthe claims.

In the drawing is shown a broken front elevation, partly in section, ofa dynamoelectric machine provided with a brush-rod supporting deviceembodying this invention.

In the drawing, the invention is shown as being applied to adynamo-electric machine having a. stationary field member 11, providedwith windings 12 and 13, and a rotary armature 14 having a distributedwinding 15. The armature is mounted on a shaft 16 which is supported inbearings 17, and a commutator 18 is held in place on the shaft 16, thesegments or bars of the commutator being connected with suitable pointson the winding 15 by leads 19.

A set of brushes 21 is mounted in operative position relative to thecommutator 18, on a brush-rod 23, which in turn is supported in positionby the brush-rod support or, fork 24, the latter being suitably held inplace, as by being secured by bolts 25 and nuts 26 to a portion of aframe or yoke 27, suitably fixed in position. The support 24 is ofconducting material and is insulated from the bolts 25 by an insulatingbushing 28 and from the yoke 27 by an insulating washer 29. A nut 26 mayalso serve to hold a lead or terminal member 31 in electrical engagementwith the support 24, an insulating washer 31 being used to insulate thelead 31 from the nut 26 or a bearing washer associated therewith.

As shown in the drawings, the support 2 1 comprises a body portion 35and a perforated vertical extension 36 therefrom, through which thebolts 25 pass to secure the support in fixed position relatively to theyoke 27. The body portion 35 has side portions 37 and 38 adjacent thelower edge. The ends of the portions 37 and 38 are provided with arms 39and 41, respectively, in which the brush-rod 23 is supported and held. Athird arm 42 projects from an intermediate point of the body portion andis parallel to the supporting arms 39 and 41, and also serves as asupport for the brushrod 23. The portion 37 and its arm 39 may be ofapproximately the same cross-sectional area as the portion 38 and itsarm 41. Strengthening ribs 13 and 44 may be provided between the bodyportion 35 and the laterally extending portions 37 and 38, respectively.

If the body portion 35 were of solid construction, the electrical pathbetween the commutator bars and the extension 36, through the brushsupporting arm 42, would be of considerably less resistance than thepaths through the supporting arms 39 and 41. The operating result ofsuch a construction would be that a greater part of the current wouldflow through the arm 42 and the immediately adjacent brushes, causingsuch heating of these brushes as would further lower the resistance ofthis path and finally cause these brushes to grab practically the totalcurrent and these currentcarrying parts to become unduly heated.

In accordance with this invention, the body portion 35 is of suchconstruction as to prevent these undesirable operating results. The bodyportion 35 may be cored or hollowed out to insure that the onlyelectrical paths between the commutator bars and the extension 36,through the arm 42, are through a portion 45 at the lower side of thebody portion and a portion 47 at the upper side thereof, and through aportion 46 at the lower side of the body portion and a portion 48 at theupper side thereof, the portions 45 and 46 being of approximately thesame dimensions. With this construction, the electrical paths betweenthe commutator bars and the extension 36 are such as to causeapproximately equal distribution of the total current between thesupporting arms 39, 41 and 42, the current in the arm 42 dividingbetween the portions 45 and 46, and avoiding such a short path betweenthis arm and the extension 36 as would exist if the body portion 35 wereof solid construction.-

It will be apparent that the arms 39 and 42 form parallel. circuitsbetween the commutator bars and the portion 47, and that the arms 41 and42 form parallel paths between the commutator bars and the portions 48,and, further, that the portions 47 and 48 form parallel connectionsbetween the supporting arms 39, 41, 42 and the portion 36.

It may be considered that the parts of the body portion connecting theportions 47 and 48 to the portions 37, 45 and 38, 46, respectively,constitute spaced portions forming parallel paths, or parts thereof, between the brush-supporting arms 39, 41, 42 and the terminal part 36.While the terminal or supporting portion of the brushrod support is inthe form of an extension 36, this portion or extension may be of anysuitable dimensions which may even be reduced to practically zero, inwhich case the terminal connection would be made at the point of unionof the portions 47, 48.

It will be apparent that, in case a greater number of brush-rod supportsthan three are required, the general principle of divided paths,outlined in connection with the embodiment of this invention describedabove, may be utilized to prevent grabbing or hogging of current by anyparticular group of brushes.

It should be understood that it is not desired to be limited to theexact details of construction shown and described, for Ohviousmodifications will occur to a person skilled in the art.

It is claimed and Letters Patent 1. A brush-rod support of electricallyconductive material and comprising a body portion, and rod-supportingprojections therefrom, said body portion comprising spaced portionsforming parallel paths in circuit with said rod-supporting projections.

2. A brush-rod support of electrically conductive material andcomprising a body portion, and rod-supporting projections therefrom,said body portion comprising spaced portions electrically connectedtogether at one end and electrically connected to said rod-supportingprojections.

3. A brush-rod support of electrically conductive material andcomprising a body portion, and rod-supporting projections therefromgreater in number than two, said body portion comprising spaced portionselectrically connected together at one end, and the other end of each ofsaid spaced portions being electrically connected to an intermediate oneand an end one of said rodsupporting projections.

4. A brush-rod support of electrically conductive material andcomprising a body portion, and spaced rod-supporting projections greaterin number than two from said body portion, said body portion forming aplurality of separate paths between a terminal portion of said supportand said spaced rodsupporting projections.

A brush-rod support of electrically conductive material and comprising abody portion, a terminal extension therefrom, and a plurality of spacedrod-supporting projections from said body portion extending in adirection opposite to said terminal extension, said body portion formingtwo spaced paths between said terminal extension and said rod-supportingprojections.

6. In combination, an electrically conductive terminal member, and abrush-rod support of electrically conductive material in electricalengagement with said terminal member, said brush-rod support comprisinga body portion and three spaced, rod-supporting projections therefromand integral therewith, said body portion being cored or hollowed toform two electrical paths between said terminal member and saidrodsupporting projections, and each path-formdesired to secure by ingportion being in the electrical path through an intermediaterod-supporting projection and a projection adjacent said intermediateone.

7 In a dynamo-electric machine, a current collecting device, a pluralityof brushes in operative position relative thereto, a rod on which saidbrushes are mounted, a support of electrically conductive material forsaid rod and comprising a body portion, a terminal portion, and aplurality of projections greater in number than two from said bodyportion, said rod being mounted on and in electrical engagement withsaid projections, and said body portion being cored or hollowed out toprovide two electrically parallel paths between said rod-supportingprojections and said terminal portion whereby current flowing betweenthe commutator bars and said terminal portion divides into approximatelyequal parts through said rodsupporting projections.

S. In a dynamo-electric machine, a cur rent-collecting device, aplurality of brushes in operative position relative to saidcurrent-collecting device, a rod on which said brushes are mounted, anelectrically conductive support for said rod comprising a terminalportion and a body portion having three spaced projections, said rodbeing mounted on and electrically connected to said rod-supportingprojections, and said body portion being cored or hollowed out toprovide two separate and electrically parallel paths between saidrod-supporting projections and saidterminal portion whereby currentbetween said commutator and said terminal portion may be caused todivide into three approximately equal parts through said rod-supportingprojections and into two approximately equal parts through the spacedpath-forming portions of said body portion.

9. In a dynamo-electric machine, a commutator, a plurality of brushesdisposed in operative relation to said commutator, a rod on which saidbrushes are mounted, and a rod support of conducting material comprisinga terminal portion and a body portion, and a plurality of spacedprojections greater in number than two from said body portion, said rodbeing supported by and electrically connected to said projections, andsaid body portion being cored or hollowed out to provide parallelelectrical paths between said rod-supporting projections whereby thecurrent between said commutator and said terminal portion may beapproximately equally distributed through Copies of this patent may beobtained for five cents each, by addressing the said brushes and saidrod-supporting projections.

10. In a dynamo-electric machine, a current-collecting device, aplurality of brushes bearing thereon, a rod on which said brushes aremounted, an electrically conductive support for said rod comprising abody portion and a plurality of projections greater in number than twofrom said body portion, said rod being mounted on and electricallyconnected to said projections, and said body portion being cored orhollowed out to provide two electrically parallel paths between saidrod-supporting projections and a terminal portion of said supportwhereby current between the rod-supporting projections and the terminalportion may divide into two approximately equal parts through saidpath-forming portions.

11. A brush-rod support of electrically conductive material andcomprising a body portion, and rodsupporting projections therefromgreater in number than two, said body portion comprising electricallyseparate and parallel portions electrically connected together at oneend, and the other end of each of said electrically separate andparallel portions being electrically connected to a plurality of saidrod-supporting projections.

12. A brush-rod support comprising a body portion, and rod-supportingprojections therefrom, said body portion comprising portions formingmultiple paths electrically separate in part and in circuit with saidrod-supporting projections.

13. In combination, a plurality of brushes adapted to cooperate with acurrent-collecting device of a dynamo-electric machine, a rod on whichsaid brushes are mounted, a brush-rod support of electrically conductivematerial and comprising a body portion, and spaced rod-supportingprojections extending from said body portion and greater in munber thantwo, said rod being mounted on and in electrical connection with saidsupporting projections, and said body portion forming a plurality ofseparate and electrically parallel paths for current flowing betweensaid current-collecting device and a terminal portion of said support.

In testimony whereof, the signature of the inventor is afiixed hereto inthe presence of two witnesses.

IVILLIAM H. POIVELL.

Witnesses:

H. C. CASE, J. J. KANE.

"Commissioner 0! Patents,

Washington, D. C.

